Fuel pump



S. WILTSE Jan. Z1, 1936. r

FUEL PUMP Filed Jan. 25, 1952 5 Sheets-Sheet 1 Z. a oO O www w s y M. A/ 7 @fw/W? f ---1L c f .ww bf a/ 1 www n w .M

n INVENTOR. Sumner Wilte l BY' ATTORNEY.

*'Jan- 21, .1935 s. wlLTsE .FUEL PUMP Filed Jan. 25, 1932 3 Sheets-Sheet 2 INVENTOR. ,Sumner /l/f/ee ATTORNEY.

Patented Jan. 21, 1936u r,UNITED STATES PATENTl OFFICE FUEL'PUMP e Sumner Wiltse, Dearborn, Mich. Application January Z5, 1932, Serial No.v 588,736

'12 Claims.

This invention relates to pumps of the diaphragm type and particularly to pumps especially designed'for use as a fuel pump for an internal combustion engine.

In Viewof the present day tendency in the automotive industry towards higher and higher speeds and the desire to obtain very rapid acceleratlon, it has been found that the vacuum tanks heretofore most commonly employed for drawing the fuel from the gas tank and delivering it to the carburetor are in many casesl noty quite equal to the requirements of high speed quick acceleration operation and, therefore, the trend in the industry today is more and more towards the use of fuel pumps to replace` thevacuum tanks. Such fuel pumps as have to date been adapted, atleast as far as I am aware, depend upon the camshaft operated fuel pump is due to the rapid reciprocation of suchpump at high speeds with 4consequent high fluid friction, hence, high temperature and vaporization of the fuel, and

the resultant production of vapor locks in the fuel line with a consequent failure of the pump to functionl and deliver the required quantity of fuel. v

The principal object of the present invention is to produce a new and improved construction in a fuel pump for internal combustion engines in which theobjections inherent to vacuum tanks and camshaftl operated fuel pumps will be oblviated.4 v

` l Another objectI of the invention is to provide a new and improved construction for a fuel pump in which the pumping action is relativelyv slow and of such a nature that practically no appreciablefluid friction is developed and the formation of :vapor locks is prevented. r

' A further object is to provide a, fuel pump which will deliverthe fuel at a pre-determined uniform the suctio l pressurev asirequired by the 'engine and `carburetor.

Anothe A, nokethereofis causedto be effected by the creation ofv avacuum on one sideof a exible diaphragm and the discharge stroke is efbject is .to provide, apumpin which (Cl. S-152) `fected by the pressure of a spring which is so designed as to insure a practically' constant pressure of the fuel throughout the entire discharge stroke. i

A further object is to provide a pump of the character described in which the vacuum for effecting the suction stroke of the diaphragm is furnished by two or three different sources which are automatically made effective as determined Iby operating conditions.

Another object is to provide a pump of the ycharacter described in which the suction stroke is automatically effected either by suction in the intake'manifold, suction from the intake of the oil pump or suction produced by a plunger actuatedby a cam incorporated in the engine structure but which is not normally in operation when the suction from either of the two rst mentioned sources is sufcient to effectively operate the pump.

A further object'is to provide a pump of the character described in which a shaft is secured to, and in axial alignment with, the pump diaphragm reciprocates with said diaphragm and its reciprocation is employed to actuate a valve automatically at the ends of the stroke of the diaphragm to place the under side of the diaphragm alternately in communication with the source ,of suction or with atmospheric pressure.

Another object is to provide a construction in which the full stroke of the diaphragm of the pump will be insured on each reciprocationthereof.

A further `object is to provide a pump inwhlch there is a minimum clearance and another object is to provide a device of simple construction that can readily be employed for manual priming of the pump, should such priming becomel necessary. o l

The above and further objects of the invention will be apparent to those skilled in the art from the following more detailed description and by reference to the accompanying drawings wherein I have shown, by way of illustration, a satisfaccordance with the invention, a part thereof being shown in elevation; Fig. 2 is an enlarged view of thecentral shaft of the pump with'the valve and vFig. l 4is ak centralfvertical Asection through a fuel pump constructedI in. ac-

valve'lactuatingI means operated thereby; Fig. 3l f I is an enlarged sectional detail on the line13-3 of Fig. 1;.Fig. 4 is a section on the line 4-4 of Fig. 2; Fig. 5 is an enlarged detail showing the hand priming device in position for the priming operation; Fig. 6 is a side elevation, partly in section, and showing the cam operated cylinder and plunger for producing suction, and Fig. 7 is a plan view of the bottom closure member for the pump casing shown in Fig. 6.

As most clearly shown in Fig. 1 of the drawings', the pump includes a casing formed by a lower member i8 and an upper member i i, each of said members being provided with lateral flanges with which any suitable fastening means, such as the screws i2, are engaged for securing the casing members together in assembled condition. Clamped between the flanges of the casing members is a pump diaphragm t8, which may be of any suitable construction. The upper casing member BI is provided with a lateral extension or boss i4, provided with a conduit i5 that communicates with the pump chamber I6, formed as clearly shown, by the casing members l@ and lll in assembled condition and in which chamber iti the diaphragm i3 is located. The lateral extension i4 of the casing member il, is provided with an annular seat Ilia surrounded by a periphery flange il for the reception of a settling chamber or sump t8 throughf which the fuel passes in its travel from the gas tank to the fuel pump. The chamber i8, in accordance with the usual construction of devices of this character, is preferably constructed of glass and is held in position against its seat by means of a bail I9 which is pivotally connected at its upper end to the extension I4 and carries at its lower end a knurled threaded nut 2U adapted to engage the rounded protuberance 2I of the chamber I8 so as to clamp the said'chamber in fluid tight engagement with the seat |611, a sealing gasket or washer 22, preferably being interposed between said chamber I8 and the seat Ia.

'I'he lateral extension I4 also includes a conduit 23, which at one end terminates in a pipe threaded counter bore in which may be screwed the end of a pipe which communicates with the gas tank. The other end of the conduit 23 terminates in a downwardly extending nozzle portion 24 which communicates with the interior of the chamber I8. A sediment collecting screen 25 is seated within a small annular recess provided in the upper face of the chamber I8 and has a central aperture adapted to fit snugly over the reduced lower end of the nozzle 24. Communication between the interior of the chamber I8 and the conduit I5 is established through a small lateral extension 26 of the conduit I5 under'the control of a valve 21 which may be of any suity chamber I6, with an upwardly extending hollow screw threaded boss 28a to which may be secured a pipe leading to the carburetor and communication between the pump chamber I6 and the carburetor is established under the control of a. ball valve 80 adapted normally toseat upon an annular valve seat provided at the lower end of the boss 29a for its engagement. The ball valve 30 annular iiange 33 which deiines a cylindrical chamber S4 for the reception of a coil spring 35 and the bottom of said cylindrical chamber is closed, except as presently to be described, by a continuation 3B of the flange 33. The continuation 36 of the ange 33 merges into and is integral with a bearing boss 3l', the bore of which is substantially in axial alignment with the pump chamber I5. Mounted for reciprocation within the bearing boss 31, is a central diaphragm shaft 38 which at its upper end is reduced and screw threaded to pass through a suitable aperture provided at the center of the diaphragm i3. The diaphragm I 3 is clamped in assembled relation with the shaft 38 by means of a pair of small cup-shaped dise washers S9, one located on each side of the diaphragm and by a nut 4l@ andsmall washer 4i, the nut 4I] being in threaded engagement with the screw threaded end of the shaft 38; a washer 42 is preferably interposed between the lower side of the diaphragm 88 and a shoulder of the shaft 38.

The lower end 38a of the shaft 38 is slidably engaged within a hollow boss or bearing 43, preferably formed integral with a bottom closure member or cap 44, secured to the lower flanged end of the casing member I8 by any suitable means such as the'screws 45. Intermediate its ends the shaft 38 is reduced inY diameter as indicated by the reference character 38h, to provide a pair of spaced shoulders 38C and 38d. Located between the shoulders 38C and 38d and straddling the reducedportion 3812 of the shaft 38 are the arms 46a of the yoked end of an actuating lever 46. At itsother end the lever 48 is pivotally connected by means of a pin 4l! with a cooperating or combination valve actuating lever 48, the two valve actuating lever members 46 and 48 forming a composite jointed lever for the actuation of a valve 48 by the reciprocation of the shaft 38. This composite lever is supported by means of the pivot pin 4l in a bracket 58 which projects upwardly from the bottom closure cap 44 of the pump casing. The lever member 48 provided with a pair of laterally extending arms 48a, each of which is notched adjacent to its outer extremity for the reception of one end of a coil spring 5I. The other ends of the springs 5I are engaged with the similarly notched ends of a pin 52 which is secured within the downwardlyextending flanged portion of the lever member 46. The member 46 is provided with a pair of laterally projecting stops 4Gb and 46c adapted to engage with the lower face of the flanged continuation member 38 of the lower casing I0 and the upper face of the closure cap 44 respectively. The lever member 48 is provided intermediateA its ends with a notch or slot 48h in which is adapted to be .engaged the reduced and 59. The conduit branches 58 and 59 terminate in and communicate with the valve chambers 6I! and 6I respectively in whichlare seated the ball valves 62 and 63 respectively. The valve chambers 60 and 6I are located within the ex,' ternally threaded bosses 64 and 65 which are adapted to be connected the coupling members 66, 61, which serve to connect to said bosses the ends of the pipe lines 68, 89 respectively. Secured between the end of each pipe line and the boss towhich it is connected, is a valve retaining plug 10, such as shown at the left hand side of Fig. 3.

The pipe line 68 is connected at its other end to any suitable source of suction, as for example, the inlet side of the oil pump of the internal combustion engine to which the fuel pump is intended to deliver fuel while the other end of the pipe line 69 is in communication with another potential source of suction, such as theintake manifold of said engine.

A pump constructed in accordance with the principles of the present invention may also inend thereof has secured to it, in any suitable way, a small cup-shaped washerv 13 of the type commonly used-in air pumps. or walls of said washer are preferablyurged into engagement with the walls of the cylinder 1I by means of asmally coil spring l14. At its other end the plunger 12 is provided with an enlarged head 15. 'Preferably seated within the outer face 'of the head'15 is a hardened wear plate 16 with which is adapted to engagea cam throw 11 of a small camshaft 18 provided within the crankcase of the internal combustion engine and adapted to be driven from the crankshaft, or any other rotating part of the engine, by any suitable driving means, not shown. It will be noted that the cylinder 1| is located substantially centrally of a flange 19 of the pump casing I0 and that said flange is adapted to be secured to the crankcase 8D of the engine and so that the cylinder 1| with the plunger 12 projects into the interior of said crank-case. vThe plunger. 12 is normally urged by means of a spring 8| outwardly of its cylinder 1| so as to cause the wear plate 16 to engage with the cam throw 11.v

It will be noted upon inspection of Fig. 1 of the drawngs'that the valve member 49 with its composite yactuating lever is located within a cham' ber 82 formed in the lower end of the casing member Il). Communication isestablished between the chamber 82 and the cylindrical portion 34 of the Acasing member I0 in which the spring 35 is mounted, through one or more apertures 83 formed in the lateral continuation 36 of the liiange 33.

The lower end of the bearing boss 43 for the 'lower end of the shaft 38 is adapted to be closed by an internally threaded cup-shaped ca p member 85, which, when the pump is in normal operating condition is screwed tosaid yboss 43 in the manner shown in Fig. 1. For'the purpose of Aenabling the pump to be readily primed by manual operation the cap,v 85 is provided with a small y shaftlike extension 86 which at its outer end is The side flanges f per-casing member II is connected withl the gas supply tank of an internal combustion engine by any suitable piping means and that the cap, or

plug 32 at the upper end of the boss 29a. of the .no gasoline in the carburetor, yand theiioat valve thereof is open, sucient suction will be produced in the fuel line,A leading from the fuel pump to the carburetor to cause the valves 30 and 21 to be raised from their seats and the suction through the carburetor will cause the fuel to be drawn directly from the gas tank through the pump above the ldiaphragm I3 without any reciprocation of the diaphragm being effected.

When the engine is operated the suction produced in the intake manifold, particularly when the engine is idling, at which time said suction is greatest, will be effective through the ypipe 69 to the fuel pump and said suction will raise the valve 63 off its seat, the suction then being communicated through the conduit 58 and branch conduit v51 and the aperture 55 to the chamber 82 thence through the aperture 83 to the under side of the diaphragm I3. The'spring 34 which normally urges the diaphragm I3 upwardly is of suiiicient strength to deliver fuel from the pump chamber I6 to the carburetor, but is not strong der 38e of the shaft 38 will have engaged with thev arms 46a of the composite valve actuating lever formed by 'the members 46, 48 and will cause said'arms to move downwardly until the lever member 46 rotating on its pivot causes the springs 5I to' be-moved past center thereby to exert a downward pull on the lever member 48 that causes the valve 4 9 to be drawn toits lowermost position of travel and bring the valve seating surface 48c at the lower end of the valve member 49 into engagement with the valve seat 56, -thus closing the aperture 55 and cutting off the underside of the diaphragm I3 from .the source of suction. The movement of the valve 49 to its lowermost position ycauses the valve seating surface 49h at the upper end thereof to move out of engagement with the valve seat 54 thereby to establish communication between the underside "of'the diaphragm and the atmosphere. Fig. 1 of the drawings shows the parts when the condition just described has been established. The

shutting off of. the communicationvbetweeny the source of suction and the underside of the diaphragm permits the spring 35 which has been compressed by the action just described, to begin to function. It will be assumed that the downward movement of the diaphragm just described has drawn a charge of fuel through the conduit 23, nozzle 24, chamber I8 and conduits 26 and l5 into the pump chamber I6; the suction produced by the downward movement of the diaphragm in the pump chamber I6 of course causes the ball valve 21 to be raised from its seat and the ball valve 3D to be drawn to its seat. As the spring 35 begins to function the diaphragm I3 will be moved slowly upwardly by the action of the spring thereby causing the uid within the pump chamber I6 to be ejected from said chamber past the valve 30, the pressure produced within the pump chamber causing the valve 30 to open and the valve 21 to close. If, during the upward movement of the diaphragm, a sufficient amount of fuel has been delivered'to the car. buretor to cause the float of the carburetor to close the carburetor float valve and thereby produce a back pressure in the fluid being delivered into the carburetor which. results in a greater pressure being developed on the upper side of the diaphragm than the spring 35 is able to'overcome, the upward movement of the diaphragm and the shaft 3B will cease until the carburetor float valve is again permitted to open thereby reducing the back pressure in the delivery line of the fuel pump and permitting the diaphragm to resume its pressure stroke. As the diaphragm approaches its upper limit of travel, the shoulder 38d will engage with the arms 46a of the lever 45 and will move the same upwardly until the springs I, having been moved past the pivotal center of the composite lever 46, 48, will cause the lever 48 to be snapped upwardly carrying with it the valve 49 and bringing about the closure of the aperture 53 which leads to atmosphere and the opening of the aperture 55 which communicates with the branched conduit 51 connected to the sources of suction.

AAs the suction within the intake manifold is greatst during the idling stroke but is markedly reduced when the engine `is operating at highest speeds, or under very heavy loads, the pump might not operate with its highest efficiency to deliver the requisite amount of fuel under allvconditions if the suction in the intake manifold alone were relied upon .to produce the suction required to bring about the suction stroke of the diaphragm I3. In ,order to provide forthiscontingency the fuel pump is also connected toasec- 'ond sourceof suction, namely, the intake side of the-oil pump of the engine, this connection being made through the pipe 68. As above pointed out,

`the suction in intake manifold is reduced at high speeds, but as the speed of the oil pump increases proportionately with the speed and rotation of the engine, the suction at the intake side of the oil pump will, therefore, be increased when the engine is operated at high speed and consequently at a high speed engine operation the suction within the pipe line 68 will be higher than that within the Vpipe line 69. When these conf ditions arise the ballv valve 62 will be raised from its seat while the ball valve 63 will be closed and the suction produced on the underside of the diaphragm will then be that of the suction produced in the pipe line 68. Of course, when the engine is operated at low speed with comparatively small loads, the suction on the intake side of the oil pump will not be as'great as that cated within its cylinder 1I.

within the pipe line 69 and the ball valve '62 will be closed while the ball valve 63 will be opened.

While it has been found that for ordinary conditions the provision of the two sources of suction just described namely, intake manifold suction and suction from the intake side of the oil pump will be suicient for insuring the eiiicient operation of the fuel pump, I' may provide a third source of suction which will be brought into operation automaticallyA should either of the two sources of suction just mentioned be insufficient to insure the pumps operation. This third means of suction is shown most clearly in Fig. 6 of the drawings and comprises the cylinder 1I and plunger 12. 'Ihe spring 8l which normally tends to urge the plunger 12 into engagement with the cam throw 11, is designed to move the plunger 12 outwardly of its cylinder whenever the suction within the branch conduit 51, chamber 82 and diaphragm I3 drops belowf the'requisite amount necessary to pull the diaphragm downwardly against the action of the spring 35. Whenever this condition arises, the spring 8| will move the plunger 12 outwardly until it is engaged by the cam throw 11. When the plunger is engaged with the cam throw 11, it will be caused to be recipro- On the inward stroke of the plunger any air contained within the cylinderv 1I will flow past the cup-shaped washer 13 and through the conduit 12a and aperture 12b to atmosphere, while on the outward stroke of the plunger the sides of the cup-shaped washer will be, drawn into close fitting engagement with the inner walls of the cylinder and suction will be produced within the inner end of the cylinder thereby raising the ball valve 9| olf its seat and producing suction in conduit 90 and chamber 82 and below the diaphragm I3.

As will be seen from the foregoing a fuel 'pump constructed in accordance with the present vinvention will be operated primarily in combination with an internal combustion engine by suction induced in the intake manifold of the engine and communicated to the underside of the diaphragmv of the pump ande-that automatically, in accord-,- ance with operating conditions of the engine, such suction may be developed below the pump dia-v phragm by the suction induced in the intake side of the oil pump; that the invention also contemplates the possible, but notv essential, use of a third source of suction developed by what may.

be termed an additional mechanically operated accessory driven by a rotating part of the engine and which accessory includes a plunger or piston reciprocating in a suitable cylinder.

As hereinbefore pointed out the fuel pump is so constructed that it will be primed directly by the suction produced in the intake manifold when the choke valve of the intakeairline for the fuel mixture is closed. As a result a pump constructed in accordance with the invention may bel primed much more quickly than is the case with gfuel pumps of the type now commonly used in which the reciprocation of the pumping media is effected entirely by mechanical means driven by a rotating part of the engine. The pump of the presentinvention also includes a convenient hand priming means. i

As will be readily understood from the foregoling description and the accompanying drawings,

thefuel pump herein disclosed will operate at a relatively slow speed because, as will be seen, the diaphragm I3 will always travel through its full stroke due to the fact that reversal of the diaphragm is effected by the alternate establishing of be closed, the back pressure in the delivery or.

foutlet line of the fuel pump produced by the closing of the carburetor float valve will be suicient ternation4 as said diaphragm reaches the ends communication between its underside with one of the sources of suction and the atmosphere, and this alternate establishment of communication is effected by the operation of the valve 49, which in turn is only caused to be moved from one position to another when the diaphragm in its movement, either upwardly or downwardly, reaches its limit of travel. The fuel pump, therefore, is a pump of constant stroke and fixed displacement. Its speed of operation will depend entirely upon the requirements ofthe engine for fuel. For example, if it be assumed that the diaphragm is traveling upwardly and delivering fuel through the pipe line that leads to the carburetor and a sufficient quantity of fuel has been fed to the carburetor such as to cause the float valve thereof to stop the upward travel of the diaphragm and this travel will not again be resumed until the float valve of the carburetor is again opened after which the diaphragm vlwill continue itsupward travel until its full strokel has been completed and the valve' 49 operated to again place the underside of the diaphragm in communication with one of the sources of suction. It will be understood that there may be any number of interruptions or pauses in the upward travel of. the diaphragm but that its downward stroke'will proceed uninterruptedly after the underside of the diaphragm is placed in communication with the source of suction. From what has just been stated itwill also be seen that the pump Lis a variable speed pumpv but of constant stroke and fixed displacement.

While I have shown by way of illustration an embodiment of the invention that has worked highly satisfactorily in actual operation, it will be understood that the invention is not limited to the specific constructional details shown and described. For example, the'use ofA check valves in certain of the conduits is not absolutely essential, nor is the use/of a sump in the line between the pump and the gas tank. Likewise, the

pumping compartment and a suction receiving compartment, each of which compartments occupy in alternation a common volumetric space,- said fuel pumping compartment havinga fuel' inlet and outlet, resilient means in engagement with said diaphragm and normally urging'it with a predetermined maximum yielding pressure to perform a pumping stroke, a reciprocating guide shaft secured to said diaphragm in axial alignment therewith for preventing objectionable distortion of saddiaphragm, a pair of spaced valve seats having ports for alternately establishing communication between said motor chamber and sources of vacuum and atmosphere, a valve freely mounted for frictionless movement between said pair of valve seats and provided with valve seating surfaces for engagement with said seats, and lost motion connections between said Ivalve and guide shaft to cause said valve to be actuated into engagement with said seats in alof said working chamber,A said connections including a lever extending between said valve and shaft and spring means .coacting with said lever normally to hold said valve in engagement with one or the other of. said valve seats.

2. In a fuel pump for use in conjunction withcentral part, resilient means for normally urging said diaphragm in a direction -to perform a pumping stroke, means for alternately connecting said suction receiving compartment to a source of suction induced by the operation of the engineV and to atmosphere, including a pair of spaced valve seats, a valve freely'mounted for movement between said seats and having a pair of valve seating surfaces for engagement with said seat, a freely mounted jointed two-part lever extending 'between and loosely supported by said guide .shaft and valve and over-center spring means for causing said lever -normally to hold one or the Vother of the valve seating surfaces of said valve in engagement with one or the other of said valve seats.

3. In a fuel pump for use in conjunction with an internal combustion engine, la housing assembly having a pump chamber and pumping means therein, motor lmeans 'for the pumping means also within 'the housing assembly, a cover plate"` detachably secured to said housing assembly and defining therewith a valve chamber communicating with the motor means, said cover plate being provided with a main conduit cornmunicating with said valve chamber and a plurality of sources of vsuction induced by the operation of said engine, means for closing communication between certain of said sources of suction and said chamber, a valve operated by said motor means and controlling communication between said main conduit and valve chamber, and means for establishing 4communication between said valve chamber and another of said sources of suction upon one becoming inoperative.

y 4. Ina fuel pump for useinconjunction with an internal combustion engine, said pump comprising housing means defining a working chamber,

a flexible diaphragm mounted f or reciprocation l shaft, a cover plate detachablyv secured to said housing and defining therewith a motor chamber, a pair of apertured valve seats for alternat-ely establishing communication between said suction receiving compartment and sources of suction induced by the operation of said engine and with the atmosphere, a valve freely mounted:

phragm and resilient means connected to said lever to cause it to hold said valve normally in engagement with one or the other of said valve seats.

5. In. a fuel pump for use in ,conjunction with an internal combustion engine, a casing structure, a pumping chamber portion and pumping means therein, motor means for controllingly driving said pumping means, including a valve chamber, a portion also within said casing structure and located below said pumping chamber and provided with valved inlets for furnishing communication between sources of suction and atmosphere, a suction inlet being in the lower-mostwall of said valve chamber portion whereby any water of condensation formed within said valve chamber will gravitate towards said suction inlet to be carried o by said suction thereby to prevent accumulation of said water within said pump.

6. An operating motor for a fuelpump particu? larly adapted for use with an internal combustion engine, said pump having a housing defining a working chamber, a eXible diaphragm mounted for reciprocation within said chamber land di- Viding it into a fuel pumping compartment and a motor compartment, a guide shaft connected to the central part of said diaphragm, a bearing for said shaft located in axial alignment with the center of said diaphragm and the motor charnber, said shaftprojecting into the motor charnber, a cover plate for said motor chamber having a bearing for said shaft, a pair of spaced shoulder portions carried by a central part of said shaft, a pair of apertured Valve seats for alternately establishing communication between the motor chamber and atmosphere and between said chamber and sources of suction induced by the operation of said engine, a valve freely mounted inV said valve chamber for movement between said valve seats to make and break such communication, a freely mounted toggle lever extending between said valve and said guide shaft and comprising a pair` of yoked end lever arms pivotally connected adjacent the center of said toggle lever, the yoked end of one of said lever arms spanning the central part of said shaft to be engaged by said shoulder portions and said valve having spaced shouldered actuating portions and anI intermediate part spanned by the yoked end ofthe other of said levers, and over-center spring means connected to said lever arms and crossing the center of said toggle lever to cause it to hold said valve normally in engagement with one or the other of said valveseats.

7. An operating motor for a fuel pump particularly adapted for use with an internal combustion engine, said pump having a pumping diaphragm, yielding means for causing it to effect a pumping stroke at a substantially constant pressure, a guide shaft connected to said diaphragm, a freely mounted frictionless valve for establishing communication between the underside of said diaphragm alternately with a source of suction and the atmosphere, a frictionless freely mounted lever between said valve and guide shaft and having lost motion connection with said shaft, and means for connecting said valve automatically with a source of suction caused by a piston and cylinder mechanically operated from a rotating part associated with the engine.

B. An operating motor for a fuelpump particularly adapted for use with an internal combustion engine, said pump having a pumping diaphragm, yielding means for causing it to effect a pumping stroke at a substantially constant pressure, a guide shaft connected to said diaphragm, a freely mounted frictionless valve for establishing communication between the underside of said diaphragm alternately with sources of suction and the atmosphere, a frictionless freely mounted lever between said valve and guide shaft and having lost motion connection with said shaft, and means for connecting' said valve automatically with sources of suction, said sources of suction being the intake manifold of the engine, the intake side of the engines oil pump and a piston and cylinder mechanically operated by a rotating part associated with the engine.

9. An operating motor for a fuel pump particularly adapted for use with an internal combustion engine, said pump having a pumping diaphragm, yielding means for causing it to effect a pumping stroke at a substantially constant pressure, a guide shaft connected to said diaphragm, a freely mounted frictionless valve for establishing communication between the -underside of said diaphragm alternately with sources of suction and the atmosphere, a frictionless freely mounted lever between said valve and guide vshaft and having lost motion connection with said shaft, and means for connecting said valve automatically with sources of suction, said sources of suction being the intake manifold of the engine, the intake side of the engines oil pump and a piston and cylinder mechanically operated by a rotating part associated with the engine, and means for operating said piston and cylinder only when said other sources of suction are inadequate.

10. An operating motor for a fuel pump rparticularly adapted for use with an internal combustion engine, said pump having a housing dening a working chamber, a exible diaphragm mounted for reciprocation within said chamber and dividing it into a fuel pumping compartment and a suction receiving compartment, each of which compartments occupy in alternation a common volumetric space, a valve chamber characterized by a guide shaft connected to the central part of said diaphragm, a bearing for said shaft located in axial alignment with the center of said diaphragm and the valve chamber belowv vtion of said engine with the atmosphere, a valve freely mounted in said valve chamber formovement between said valve seats to establish and interrupt in alternation communication between said sources of suction and the atmosphere, a freely mounted toggle lever extending between said valve and said guide shaft and comprising a pair of yoked end lever arms pivotally connected adjacent the center of said togglelever, the yoked end of one of said lever arms spanning the reduced central portion of said shaft to be engaged by said shoulders, and said valve having a reduced central portion spanned by the yoked end of the other of said levers, and resilient means connected to said lever arms and crossing the center of said toggle lever to cause it to hold said valve normally in engagement with one or theother of said valve seats. L

11. An operating motor for a fuel pump of the type particularly adapted for use with an interl nal combustion engine and having a housing detween said valve seats to establish and interrupt in i ning a Working chamber with aflexible diaphragm mounted for reciprocation within said chamber and dividing it into a fuel pumping compartment and a motor compartment, said housing having a central bearing located in axial alignment with said diaphragm and an annular space between said bearing and the outer walls of said housing, and said housing being further provided with an open recess below said Working chamber, a cover plate detachably secured to said housing and defining with said recess a valve and valve operating mechanism chamber, said cover plate being provided with a bearing in axial alignment with said rst named bearing, a guide shaft secured to the center of said diaphragm and supported in said bearings, said shaft having its central portion reduced between said bearings to provide a pair of spaced shoulders, a pair of axially aligned apertured spaced valve seats, one in said housing andthe other in said cover plate, one of said valve seats providing communication between said valve chamber and atmosphere, a'conduit connecting the other of said valve seats with a source of suction induced by the operation of said engine, a valve freely mounted in said valve chamber for movement bespanned by the yoked en d of the other of said 4 lever arms, and resilient means connected to said lever arms and crossing the center of said toggle lever to cause it to hold said valve normally in engagement with one or the other of said valve seats.

12. An operating motor as set forth in claim 11 in which said cover plate is provided with a plurality of conduits each leading to different sources of suction produced bythe operation of the engine and each of said conduits having interposed therein valve means for automatically establishing communication between said valve chamber and that source of suction which at any instant is strongest. I

4SUMNER. WILTSE. 

